TW201408725A - Mixture of filing material for manufacturing thermoplastic shoe reinforcement materials - Google Patents

Abstract

This invention concerns a mixture of filling materials consisting of a bioplastic and of a specially selected naturally renewable material namely of rice husk powder at a quantity of as much as 50 weight % and polylactic acid powder of as much as 70 weight % which is suitable for manufacturing thermoplastic reinforcement materials for the shoe industry, primarily for the front and rear caps. Shoe reinforcement materials can be manufactured with the mixture of filling material of the invention both on a double belt system and with extrusion, in particular with coextrusion.

Description

Filler mixture for the manufacture of thermoplastic shoe reinforcements

The present invention relates to a filling material mixture for the manufacture of thermoplastic reinforcing materials for the footwear industry, which is mainly used for the front cover and the rear cover. The powder mixture consists of bioplastics and specially selected natural renewable materials. Shoe reinforcement materials can be made from the filler material mixture of the present invention on a two-belt system and using extrusion, especially co-extrusion.

DE 26 21 195 C describes a reinforcing material for the manufacture of sheets/sheets in which a powdery meltable plastic material which also contains a filling material is laminated on a carrier material similar to textiles. As the meltable plastic, polyethylene, vinyl acetate and copolymers thereof are used as suitable filling materials such as wood flour or chalk powder. The object of the invention is to increase the proportion of filler material in the coating while maintaining the flexural strength and stiffness of the material. It has been found that if the particle size distribution of the plastic and filler powder is approximately or equivalent, the proportion of filler material can be increased to 50%. At this point, the molten plastic particles completely surround the filler particles, allowing the filler material to act like a plastic. These materials do not have sufficient adhesive properties to allow the adhesive layer to be applied to the surface to be permanently bonded to the upper of the shoe.

EP 183 912 B2 describes a shoe reinforcement which can be directly glued to the shoe leather without any additional plastic, wherein the polycaprolactone type is used as a hot melt adhesive, which is lower at 60 ° C. Especially suitable for melting point. Further, a plastic powder which is not dissolved in a hot-melt adhesive or an organic or inorganic powder which is coated in a plastic is used as a filling material. The carrier material is applied to one or both sides of the materials, as desired. Disadvantages of such known materials It is often necessary to use a carrier material at higher temperatures to maintain the bonding and agglomeration of the material and to achieve or maintain the robustness required for machine construction in which the shoe is bonded under warm conditions. Since the shoe cover is manufactured by stamping and sharpening from the base waterproof layer, there is always waste from sharpening and cutting. Since this waste adheres to the residue of the carrier material, it cannot be recovered in the manufacturing process.

EP 1 525 284 B1 describes a mixture of hot melt adhesive/filler compounds which overcomes some of the above disadvantages. The hot melt adhesive/filler compound mixture has sufficient inherent stability due to precisely adjusted physical parameters such as melt volume index, thermal elongation, viscosity, surface tack or viscosity, so that The carrier material is treated as it is achieved by precisely adjusting the aforementioned parameters of the starting materials used. The hot melt adhesive must have an MVI value of from ^{2 to 300} cm ³ /10 min, preferably from 10 to 30 cm ³ /10 min (measured according to DIN ISO 1133 at 100 ° C, 21.6 kg). The quantitative ratio of hot melt adhesive to filler material must also be from 50 to 95% by weight to 50 to 5% by weight filler material. The filler material (spherical polygonal particles having a particle size of 10 to 500 μm) used herein is an organic, natural and inorganic mineral filler. The base waterproof layer is also made from such materials (e.g., after extrusion) from which appropriate 3 dimensional reinforcement members can be fabricated by stamping and sharpening. In addition, sharpening and stamping waste from such materials have the same composition as the substrate, which means that it is not a problem to return it to the extrusion mechanism. However, a disadvantage of these materials is that a comparable proportion of hot melt adhesive provides the internal cohesion of the compound. Especially at higher temperatures, when cooled or solidified in the case of a relatively small proportion of hot melt adhesive, it will spread out or become brittle in the longitudinal direction.

TW 201008765 is a method of making environmentally friendly soles made from recycled rice husks, wheat hulls and similar plant materials as additives. These materials are screened and then uniformly mixed with a natural elastomeric rubber using a machine to form an environmentally friendly sheet of material having a suitable thickness. This produces a material for a rubber sole that contains rice husk particles and has excellent physical properties. This manufacturing process makes it possible to manufacture environmentally friendly soles with good functional characteristics.

TW 45548 B is a "shoe manufacturing process using rice husks". In addition to rice husks, it mainly contains styrene foam waste up to 13% by weight of the entire shoe.

WO 2011/098842 manufactures polylactic acid and derivatives for environmentally friendly and biodegradable packaging primarily used in the food industry. Polymer composition (such as thermoplastic polyhydroxyalkanoate (PHA), polyhydroxybutyric acid (PHB) and inorganic filler materials (such as nano calcium carbonate) and organic filler materials (such as powdered straw, sugar cane with a particle size of 20 μm) Leaves, palm leaves or rice husks)) have improved thermal insulation properties. A typical composition consists of 71% polylactic acid (PLA), 9% PHB and 20% nano calcium carbonate. These materials are not suitable for use as thermoplastic shoe reinforcements.

Therefore, there is a challenge in finding an improved shoe reinforcement for making a shoe cover and a suitable manufacturing process. These shoe reinforcing materials should not only have improved flexural strength, thermal elongation and surface adhesion, but also have peel strength and good biodegradability and recyclability. In particular, however, such materials should be economically and environmentally friendly. Therefore, the main problem is to find a suitable filling material mixture as a raw material, on the other hand, these raw materials are naturally renewable raw materials and are especially derived from plants. On the other hand, it should contain bio-plastics, both of which can be used as filler materials, up to 75% by weight relative to the hot-melt adhesive, and do not make the thermoplastic strengthening during work and handling. The material becomes unstable and in particular does not collapse upon heating.

Surprisingly, it is possible to solve the above problems using a filler material mixture which is also compatible with known hot melt adhesives. The mixture consists of bioplastics, polylactic acid powder or recycled polylactic acid powder (PLA) and specially selected plant fibers (i.e., purified rice husks). Not only conventional powder coating techniques on dual belt systems have proven to be suitable for use as a manufacturing method. In particular, extrusion and co-extrusion in multi-channel extruders have shown that they can be applied by treating the combination of filler materials of the invention to a quantity up to 75% by weight without loss of necessary material properties (such as Thermal stability, flexural strength and surface adhesion). On the contrary, the products manufactured in this way have all the properties required for practical application, which means that they are strong as shoes. The material (ie the shoe cover) is particularly good.

The filler material component of polylactic acid or recycled polylactic acid (hereinafter referred to as PLA or r-PLA) has good biodegradability. Industrial Process PLA is widely used in a variety of applications where PLA is known for use in the packaging industry, the food industry, agriculture, horticulture, medical technology, sports and functional apparel, and composite materials. PLA is a bioplastic, but it is also a renewable raw material because lactic acid is initially obtained from sugar and corn starch and is produced by polymerization from it (which produces lactic acid).

Bioplastics are not a consistent polymer class, but a major family of multiple plastic types. Apart from this, the term is understood in different ways. Some people regard bioplastics as biodegradable plastics, while others see it as a plastic based primarily on agricultural commodities. In most cases, these are defined as overlapping. A particular feature of PLA is its good biodegradability in industrial composting facilities under certain environmental conditions, and it degrades within a few months under industrial composting conditions.

The present invention uses recovered polylactic acid (r-PLA), preferably in powder form. Two fillers (PLA and / or r-PLA and rice husk) and thermoplastic hot melt adhesives (such as polycaprolactone type (Capa type) or thermoplastic polyurethane (TPU) already used in the manufacture of shoes Or ethylene vinyl acetate (EVA)) combine to form an advantageous filler material mixture. This filler material mixture is compatible with all of these and many other thermoplastic hot melt adhesives, making it easy to handle into foils, flat rails or sheets. These materials may also be coated with a carrier material on one or both sides, as appropriate. These foils, flat rails or plates can then be stamped into a molded part in a press, and thus it can be used as a 3D model part or a front or back cover in the manufacture of the shoe. The rice husk (as a naturally recyclable plant material) which can be obtained by peeling out rice grains can be used as a filling material even when it is not dried.

The raw materials used in the present invention have the following physical properties:

a poly-ε-caprolactone type or polycaprolactone-based powdered polyurethane, wherein the molecular weight is 40,000-80,000 g / mol, and the MFI value is in the range between 2.5 and 31, Vision The type is measured at 100 ° C or 160 ° C / 2.16 kg, while the particle size distribution is between 50 and 1,000 μm.

b. a thermoplastic polyurethane or TPU in powder form having a melt flow index (MFI) of from 10 to 50 g/10 min, preferably from 25 to 40 g/10 min (at 190 ° C / 2.16 kg), The particle size distribution is between 50 and 1,000 μm.

c. an ethylene-vinyl acetate copolymer (EVA) in powder form, wherein MFI = 20-50 g/10 min + 20-40 wt% VA ratio (= vinyl acetate ratio), while the particle size distribution is between 50 and Within the range of 1000 μm.

d. rice husk powder, wherein the particle size is 1-3,000 μm, preferably 20-800 μm

e. Polylactic acid powder and/or r-PLA powder, wherein MFI = 2-40 g/10 min at 190 ° C / 2.16 kg, and a particle size distribution of 50 - 1,000 μm and a maximum residual moisture of 2500 ppm.

F. basis weight of 10-120g / m ² of water puncture perforated / non-perforated polyester felt or a basis weight of 25-120g / m ² of cotton or cotton blend fabrics may be used as the support material.

The carrier material is always used as appropriate. The melt flow index (MFI) was measured in accordance with DIN EN ISO 1133 and the flexural strength of the tested product was measured in accordance with DIN EN ISO 20864 (Domtest). The following examples give a more detailed description of the invention, but the invention is not limited to such examples. The thermoplastic reinforcing materials of the present invention can be made by extrusion or co-extrusion and by a powder coating process on a dual belt system.

A‧‧‧ melt flow

B‧‧‧ melt flow

C‧‧‧ melt flow

Figure 1 shows an example referred to as a multi-channel extruder.

Some examples of manufacturing on a dual belt system

The powdery raw material, rice husk and r-PLA are mixed in advance in a certain ratio to form a homogeneous powder mixture and agglomerate where necessary. This mixture is then processed on a dual belt system. The dual belt system consists of an endless looping upstream belt and a similar downstream belt, between the two belts. Form an adjustable gap. The powder mixture is added to the film under predetermined pressure and temperature readings and formed into a film, wherein the heat for film formation is generated by the hot plate. Film formation means that the mixture melts in a continuous operation, is pressed into a flat form, and then hardens after cooling. If it is necessary to apply the carrier material on one or both sides of the material, the powder mixture can be fed or fed in pure form onto the carrier material and treated in this manner. Unlike the dual belt system, the heat is generated by a radiant heater or an infrared radiator, and the powder is replaced by a calender roll instead of the upstream part or the down belt. Table 1 shows the readings of the reinforcement materials made on the dual belt system.

The following compositions were tested for the present invention:

1. A 50-weight rice hull coalescence powder consisting of 50% by weight of rice husk and 50% by weight of EVA powder and 15% by weight of polycaprolactone powder and 10% by weight of EVA powder and 25% by weight of r- PLA powder composition.

2. 25 wt% of the rice husk agglomerated powder was uniformly mixed with 25% by weight of r-PLA powder and 5% by weight of EVA powder and 45% by weight of polycaprolactone powder.

For comparison, the composition according to patent WO 2011/098842 was measured in the same manner as the composition of the invention.

Some examples of the reinforcing materials of the present invention are produced using an extrusion or co-extrusion process:

Simple extrusion and co-extrusion can be a great advantage in the manufacture of shoe reinforcements, and the examples or formulations presented below can be used in both processes. It means that the purified rice husk and r-PLA (both in an amount of 50 to 70% by weight) and the thermoplastic hot-melt adhesive (25 to 50% by weight in number) can be pre-agglomerated.

Manufacturing example 1

15% by weight of MFA value of 1-25 g/10 min (measured at 150 ° C, 10 kg) of thermoplastic polyurethane, 10% by weight of VA content of 20 to 40% by weight of ethylene vinyl acetate copolymer and 20% by weight of a linear polyester polyε-caprolactone having a molecular weight distribution of 40 to 80,000, and 40% by weight of the recovered polylactic acid powder and 15% by weight of a rice hull powder having a particle size of 400 to 800 μm are pre-agglomerated, and Further processing in the extruder.

Manufacturing example 2

10% by weight of ethylene vinyl acetate having a VA content of 20 to 40% by weight and 40% by weight of a linear polyester polyε-caprolactone having a molecular weight distribution of 40 to 80,000 at 35 wt% of recovered polylactic acid powder and 15% by weight Pre-agglomeration under rice husk powder and further processing in an extruder.

Manufacturing example 3

20% by weight of MFA value of 1-25 g/10 min (measured at 150 ° C, 10 kg) of thermoplastic polyurethane, 10% by weight of VA content of 20 to 20% by weight of ethylene vinyl acetate copolymer and The recovered polylactic acid powder having 45 wt% MFI (melt flow index) of 15 to 35 g/10 min and 15 wt% of rice hull powder having a particle size of 350 to 700 μm were pre-agglomerated together and further processed in an extruder.

Manufacturing example 4

50% by weight of rice hull agglomerates obtained from agglomerates of 50% by weight rice hulls and 50% by weight EVA and additionally 10% by weight of EVA and 25% by weight of r-PLA particles and 15% by weight of polycaprolactone

Comparison example: Comparative example 1

25% by weight of an ethylene vinyl acetate copolymer having a VA content of 20 to 40% by weight and 45% by weight of a linear polyester polyε-caprolactone having a molecular weight distribution of 40 to 80,000 and a bulk density of 25 g/mL of 25 g/ml residual moisture less than 9% of wood flour together with further processing, and subsequently processed in an extruder.

Comparative example 2

10% by weight of an ethylene vinyl acetate copolymer having a VA content of 20 to 40% by weight and 60% by weight of a linear polyester polyε-caprolactone having a molecular weight distribution of 40 to 80,000 and a 30% by weight bulk density of 25 g/ml and residual moisture less than 9% of wood flour together with further processing, and subsequently processed in an extruder.

If the reinforcing material of the present invention is produced according to a co-extrusion process, a multi-channel extruder is preferred. In the case of co-extrusion, several melt streams of different throughputs (layer thicknesses) and different flow properties must first be fed into the common flow channel and then flow together via this channel. So-called flow phenomena may occur when individual paint layers are combined, and such paint layers that flow together after combining the paint layers can cause problems in co-extrusion. This is the reason why a multi-channel tool must be used in the manufacture of the reinforcing material of the present invention. Each lacquer layer is formed in its own flow channel in the case of a multi-channel tool. The flow distribution of each individual layer can be corrected via the width of the retention column. The melt stream flows only together in the region of the cookware zone, which is the area immediately before the melt leaves the extruder. The thickness distribution of the entire composite can be corrected by adjusting the discharge gap. The relatively short flow length of all layers in the discharge zone is advantageous to prevent the melt from being encased or to cause the lacquer layers of the present invention to flow into each other. This makes it possible to use the multi-channel tool to excellently manufacture the reinforcing materials of the present invention, which have a combination of materials having a large difference in the thickness of the main layer and the flow properties. This application should use a multi-channel tool with 3 channels.

The final product after co-extrusion has a three-layer structure in which the core consists of a mixture of filler materials (specifically, rice husk and r-PLA) and a hot-melt adhesive, including two outer layers of an adhesive for a thermoplastic hot-melt adhesive. . This makes it possible for the core of FIG. 1 (ie melt stream A) to consist of 50% by weight of r-PLA and 25% by weight of rice hulls and 25% by weight of EVA. Furthermore, the two outer layers of the adhesive according to Figure 1 (i.e., melt streams B and C) may be comprised of EVA, thermoplastic polyurethane or polyester (such as polycaprolactone), which may range from 10 to 250 g/ The amount of m ² is applied together to the surface of this core. These adhesive layers may have a thickness of 0.1 to 2 μm, and the "core" filler material mixture (r-PLA and rice hull) may also be pre-agglomerated prior to co-extrusion as needed.

Coextrusion is particularly advantageous when the core contains up to 75% by weight of the filler material mixture, as this reduces the amount of hot melt adhesive in the core (which has substantial economic advantages). It means (the filler material in the core): (the amount of adhesive in the core) can be as high as 3:1. nuclear Variations in the composition of the material, the 3-layer structure, and the thickness of the layer in the core and the amount of adhesive in the outer layer make it possible to provide different stiffnesses and, if desired, flexural strength. Finally, there are advantages to entering and operating the shoe cover when manufacturing the shoe.

Claims (7)

A filler material mixture for the manufacture of a thermoplastic shoe reinforcement, characterized in that it consists of: a. up to 50% by weight of rice hull powder b. up to 70% by weight of polylactic acid powder wherein the thermoplastic The shoe reinforcement material contains a thermoplastic hot melt adhesive and can be obtained by extrusion and/or co-extrusion. A filler material mixture for the manufacture of a thermoplastic shoe reinforcement, characterized in that it consists of: a. up to 50% by weight of rice hull powder b. up to 70% by weight of polylactic acid powder wherein the thermoplastic The shoe reinforcement material contains a thermoplastic hot melt adhesive and is obtainable via a process on a dual belt system in which the carrier material can be applied on one or both sides. The thermoplastic shoe-reinforced material of claim 1 or 2, wherein the thermoplastic hot-melt adhesive is selected from the group consisting of up to 50% by weight of linear polyester, up to 30% by weight of ethylene vinyl acetate copolymer, and up to 50% by weight Thermoplastic polyurethanes and/or mixtures of such plastics. A thermoplastic shoe reinforcement material according to claim 1 or 2, wherein it may contain no more than 1% by weight of an inorganic filler material. The thermoplastic shoe reinforcing material according to claim 1 or 2, wherein the rice husk powder has a particle size distribution in a range of from 1 to 3000 μm, preferably from 20 to 800 μm. The thermoplastic shoe reinforcing material of claim 1 or 2, wherein the polylactic acid powder is recycled polylactic acid powder. A shoe component is manufactured using a thermoplastic shoe reinforcement material according to any one of claims 1 to 6.